What are the numbers on my lens for?

I know what a macro lens is for naturally, but my Nikon 85mm macro lens has a dial on it with numbers for feet like 3/4 etc

what are they for, what do they tell me?

You have 3 rows of numbers.
The "ft" and "m" are the focus distance, given in feet and meters, between the sensor plane and the subject.
The "1:" is the magnification ratio. Your macro lens is capable of producing a 1:1 magnification ratio. This means that the image projected on the sensor is the same size of the subject (assumes that your subject is in focus). At 1:2, the image projected on the sensor is half the size of the object.

When shooting close distances with macro lenses, it's common to manually focus by turning the focus ring and/or moving the camera back and forth. At close range, auto focus is not recommended.

It is challenging to help you without known the make and model of your camera and lens.
The numbers and markings on a lens barrel can be daunting.
This one is a Nikkor 50mm fixed focal length.
The 50mm tells us the magnification. A 50mm lens gives a "normal" view on a 35mm camera. If your camera is a compact digital, then 30mm gives a normal view. If your lens is a zoom lens then you can adjust the focal length and zoom in for high magnification (telephoto) or zoom out for wide-angle. Longer than normal focal lengths are telephoto and shorter than normal are wide-angle.
The top scale on the lens pictured is the focusing distance. This one is metric (in meters) yours is likely in feet and inches. We peer through the camera viewfinder and rotate the lens. You rotate right and then left to fine focus. Once focused the scale reads off the subject to camera distance. The is the symbol for "infinity" means the camera to subject distance is super far like the horizon or the moon.
The lens aperture adjusts the working diameter of the lens. Too far open and the lens allows too much light to enter. This will ruin the picture, it will be too light due to over-exposure. If the working diameter to too small, the picture will be ruined due to under-exposure thus too dark or all black. The aperture settings are called f-numbers. On this lens they are from tiny working diameter to large, f/22 - f/16- f/11- f/8 - f/5.6 - f/4 - f/2.8 - f/1.8. On the lens barrel the f/ is omitted for simplicity.
Speaking of reading - why not read the camera manual and maybe a book on how to do photography
Other numbers and symbols might be on the lens barrel. Tell me all the model numbers and I will help.

Focal distance.